Optimal Gateway Station Placement for Transmission Delay Minimization in Broadband LEO Satellite Communication System

Recently, broadband low earth orbit (LEO) satellite communication systems with mega constellations have drawn much academic and industrial attention, due to their powerful uninterrupted broadband service capabilities across the globe. In such a large LEO satellite system, the placement of gateway stations will affect many aspects of the system performance, such as communication data rates, transmission delay. In this paper, we investigate the gateway station placement problem in a broadband LEO satellite communication system with transmission delay minimization as the target function. The optimization problem is formulated under the constraints of the maximum on-board capacity for a single satellite, the channel capacity of the feeder link, and the location range of gateway stations (i.e., on the land of China mainland). Moreover, two heuristic optimization algorithms are adopted, which are the genetic algorithm (GA) and the simulated annealing algorithm (SA), to efficiently solve the problem. Simulation results show that SA outperforms than GA but has a higher computational complexity. In contrast, GA can give an approximate solution at a lower computational cost. Our simulation results also provide a reference design of gateway station placement for our country.